[Xy-pic] Wrong reference point in PS fonts?

[Henning Makholm]

It seems that the type1 version of the XY-pic line fonts have wrong
reference points, at least on the teTeX installation I use. If I do

$ cat usemf.tex
input xydash10 ;
$ cat foo.tex
\font\a=xydash10
\font\b=mfxydash10
\hbox{\a\char31}
\nointerlineskip\vskip 5pt
\hbox{\b\char31}
\end
$ tex foo.tex
This is TeX, Version 3.14159 (Web2C 7.3.1)
(foo.texkpathsea: Running mktextfm  usemf
/usr/local/stow/share/texmf/web2c/mktexnam: Could not map typeface abbreviation se for usemf.
/usr/local/stow/share/texmf/web2c/mktexnam: Need to update /usr/local/stow/share/texmf/fontname/special.map?
mktextfm: Running mf \mode:=ljfour; mag:=1; nonstopmode; input usemf
This is METAFONT, Version 2.7182 (Web2C 7.3.1)
[bla bla bla]
Font metrics written on usemf.tfm.
Output written on usemf.600gf (128 characters, 10464 bytes).
Transcript written on usemf.log.
mktextfm: /home/disk15/makholm/tmp/rbmm/makholm-thesis/usemf.tfm:
successfully generated.
 [1] )
Output written on foo.dvi (1 page, 304 bytes).
Transcript written on foo.log.
$ dvips foo -o 
This is dvips(k) 5.86 Copyright 1999 Radical Eye Software (www.radicaleye.com)
' TeX output 2003.06.21:0159' -> foo.ps
<texc.pro><texps.pro>. <xydash10.pfb>[1]
$ gv foo.ps

then the upper of the vertical line segments (which uses the type1
font) appears too far to the left by about .2 half a line-width. The
lower one (forced to use metafont by giving it a name that has no
type1 counterpart) is correctly placed.

The effect is more visible if I use xdvi and force the resolution up
to 2400, but whether this works for others depends on whether one's
mktexpk script prefers to create pk fonts from type1 or mf sources
(mine, inexplicably, prefers gsftopk over mf).

Has anybody observed the same or is it my installation that is br0ken
somehow?

-- 
Henning Makholm                     "However, the fact that the utterance by
                           Epimenides of that false sentence could imply the
           existence of some Cretan who is not a liar is rather unsettling."